Larch Maxey & Anor v R

For conspiracy under section 1(1)(a) of the Criminal Law 1977, the word necessarily concerns the legal character of the intended outcome, not whether the agreed conduct was certain to achieve it. The prosecution must prove an agreement, an intention to bring about the alleged outcome, and that carrying out the agreement in accordance with that intention would involve the substantive offence. In a conspiracy to cause public nuisance, section 1(2) requires intention as to the nuisance-causing consequence; constructive knowledge cannot be conspired to. Protestors may cause a nuisance through authorities responding to a safety risk, and independent judgment does not necessarily break causation. A late change in the prosecution case does not make a trial unfair where clear revised directions are given and no injustice results.

After a jury trial at Isleworth Crown Court, Larch Maxey and Julian Roger Hallam were convicted of conspiracy to cause a public nuisance arising from a planned drone protest within Heathrow’s flight restriction zone. They appealed with leave, arguing that the prosecution had not established an agreement which would necessarily involve a public nuisance, that the airport authorities’ independent judgment broke the causal chain, and that a late change to the route to verdict rendered the trial unfair. The central issues were the construction of section 1 of the Criminal Law 1977, causation through third-party safety measures, and the fairness of continuing a trial after a significant change in the prosecution case.

The appeals were dismissed. The convictions could not be impugned.

1. Conspiracy. Section 1(1)(a) of the Criminal Law 1977 requires the jury to consider the consequences of the agreed course of conduct if carried out in accordance with the parties’ intentions. The requirement that the conduct necessarily amount to or involve an offence concerns the legal quality of the intended outcome. It does not require proof that the conduct would inevitably achieve that outcome. The prosecution therefore had to prove the agreement, an intention to cause closure of Heathrow, and that carrying out that intention would involve the offence of public nuisance. Paras [22]–[25].
2. Mental element. The common-law offence was defined by reference to Rimmington [2006] 1 Cr App R 17 and the mental-element test in R v Shorrock (1994) 87 Cr App R 67. Section 1(2) required the appellants to intend that the agreed conduct would endanger the public or obstruct rights common to the public. A person cannot conspire to have constructive knowledge, even though the substantive offence could be committed where the defendant knew or ought to have known of the consequence. Paras [10]–[11].
3. Causation and innocent agency. Protestors may cause a public nuisance where their conduct creates a risk to public safety and foreseeably leads authorities to take reasonable steps which obstruct public rights. The causal chain is not broken merely because the authorities exercise independent judgment. Resort to innocent agency was unnecessary, but the court also held that the doctrine would not require an unwitting agent or exclude an agent exercising independent judgment. Paras [26]–[29].
4. Statutory comparison. The court observed that, although section 78 of the Police, Crime, Sentencing and Courts Act 2022 is differently worded and includes recklessness, a comparable causal approach may apply to protest conduct which prompts reasonable safety measures obstructing public rights. This observation was not necessary to decide the common-law charge. Para [26].
5. Fairness. Where the prosecution case changes late, particularly in a trial involving an unrepresented defendant, the judge must consider whether the jury can cope with the change and whether the defendant has been so wrong-footed that fairness requires discharge. A debate with the parties is not required in every case, but the judge must clearly explain the potential problems and the reasons for continuing. The question is whether injustice occurred on the particular facts. The judge’s revised directions were clear, and the appellants’ central case that they did not intend to close Heathrow remained unaffected. Paras [30]–[33].

1. Court of Appeal (Criminal Division) The appeals against conviction were dismissed. [2025] EWCA Crim 472.
2. Isleworth Crown Court On 15 December 2023, a jury convicted Larch Maxey and Julian Roger Hallam of conspiracy to cause a public nuisance. Case number T20197326.